Studies: 2.5% Benzoyl Peroxide Just As Effective As 10%

Benzoyl peroxide (BP) is one of the most successful OTC treatments for acne. It kills bacteria and helps to shed dead skin cells. Recent research also suggests it may mitigate genetic androgen sensitivity in acne-prone skin.

Benzoyl peroxide normally comes in 3 concentrations 2.5%, 5% and 10%, with the implied assumption that higher concentrations are more effective. But is this true? Is 10% BP really more effective than 2.5% in treating acne?

Studies say no. I stumbled on to 2 reviews that looked at studies comparing the effectiveness of different benzoyl peroxide dosages. They both concluded 2.5% BP is just as effective as 5% and 10% concentrations are.

The only thing that increased was side-effects. Benzoyl peroxide can damage the skin barrier function and increase moisture loss from the skin. This can leave the skin vulnerable to infections and inflammation and explains why BP causes dry skin for some people.

BP depletes protective antioxidants from the skin. A single application of 10% BP wipes out 93.2% of total vitamin E from the skin. Vitamin E being fat-soluble is one of the most important antioxidants in the skin. Benzoyl peroxide, especially in high doses, causes lipid peroxidation. In normal English this means BP destroys (oxidizes) fats in the skin, and this is just the type of inflammation that’s been shown to trigger the acne formation process.

You can mitigate the damage with vitamin E cream or other antioxidant creams. That’s why I recommend following BP with soothing moisturizer (even for oily skin).

This doesn’t mean you should avoid BP or that it wouldn’t work for acne. It does. The point is to understand BP has both positive and negative effects on the skin. If little bit is good then more must be better definitely doesn’t apply here.

By all means use benzoyl peroxide to treat acne. Choose 2.5% over 5% or 10% and limit it to once or twice a day. 30 minutes later follow with soothing moisturizer, BP can react with vitamin E to cause more inflammation and that’s why you should wait a bit after applying BP cream. Follow these simple steps and your skin should be better off with benzoyl peroxide.

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About Me

Hi, I am Acne Einstien(a.k.a. Seppo Pussa). I'm a bit of a science nerd who is also passionate about health. I enjoyed digging through medical journals for acne treatment gems I can share here. You can read more about my journey through acne and how I eventually ended up creating this.

References

23 thoughts on “Studies: 2.5% Benzoyl Peroxide Just As Effective As 10%

    • Belle, as much as I like and respect what Tracy does, about 90% of what she said in that video is total nonsense. I know that she has good intentions, but she’s getting her information from very unreliable sources. Basically she’s just repeating all the sensational claims in many alt-med websites.

      At one point I looked at safety of benzoyl peroxide and whether it’s absorbed systematically. The skin rapidly metabolized it to benzoic acid, a harmless chemical that the kidneys filter out very rapidly. I looked at this when I was researching whether BP is safe for pregnant women. While it’s not specifically tested in pregnant women all the articles (that is scientific studies) said it’s safe.

      Here’s a bit more reliable take on the benzoyl peroxide causes cancer thing: https://thebeautybrains.com/2008/04/08/does-benzoyl-peroxide-cause-cancer/

      Quick search on PubMed also brough up a few studies:

      Benzoyl peroxide: an integrated human safety assessment for carcinogenicity. This one mentions that 1 study found that BP increases cancer when it’s combined with acetone (an irritant and combination that’s harsher than BP alone), but there are also 6 similar studies that show no effect. Basically the one study is probably a statistical outlier.

      Photocarcinogenesis and toxicity of benzoyl peroxide in hairless mice after simulated solar radiation. Showed no increase in cancer when BP was combined with UV radiation (simulating sun exposure). The study mentioned that BP treated mouse died sooner, but that’s no applicable to humans as in humans the skin metabolizes it into a harmless chemical. This study also concluded that based on currently available evidence BP is safe to use.

      Then, is BP harsh on the skin? It can be. As I mentioned in this article it depletes the antioxidants from the skin and can damage the skin barrier function. Use too much of it and you can run into trouble. That’s why I recommend using soothing, antioxidant moisturizer after BP.

      Whether to use it or not is really up to you. I think it’s pretty fantastic stuff and really cost effective. It got rid of the remaining redness and the few pimples that no amount of diet or healthy lifestyle could fix.

  1. I’ve always thought about consuming antioxidant vitamins (C,E) prior BP application, to increase the oxidative stress resistance of dermal cells; have you come across any information regarding such thing?

    • Not specifically to address your question, but there’s data to show antioxidant supplements and reducing systemic oxidative stress is good for acne. For example, my recent post on green tea talks about studies that show how antioxidants from green tea make their way to the skin and increase resistance to oxidative stress. You can, or course, achieve the same with properly formulated antioxidant creams. I would recommend applying these creams after BP, to replenish the antioxidants BP depleted.

  2. Hi Seppo,

    Only recently discovered your site. Just wanted to say a huge thank you for your efforts, I really appreciate the work you put into researching different products and claims, and that you keep an open dialogue with your commenters. I’ve suffered from acne my whole life and while I’ve never found that ‘magic bullet’ the information and ideas you provide along with (most importantly) the science behind it make you some sort of hero.

    My Thanks,

  3. Greetings Seppo,

    I came across this blog while looking into the negative effect of benzoyl peroxide on Vitamin E levels in the skin, and the abstract in this study seems to support that:

    https://www.ncbi.nlm.nih.gov/pubmed/11522381

    I’ve been curious about this because the internet is rife with claims that the skin develops an “addiction” to BP, and all the stories of people suffering particularly terrible breakouts upon quitting it (which aligns with personal experience, I’ll add), as if they’re signs of withdrawal. For the longest time it confused me why such a thing would happen — if all benzoyl peroxide did was kill the P. acnes bacteria, then surely if one were to quit they might very well suffer a breakout, but the breakout shouldn’t be considerably worse than the ones they suffered from before starting their BP regimen (yet that appears to often be the case).

    However, if the constant application of copious amounts of BP (as prescribed by sites like acne.org and numerous others) is actually doing underlying short-term damage by destroying the skin’s natural antioxidant barrier, then it stands to reason that quitting would result in these nasty breakouts that often scare people into returning to their BP regimen. I suppose the damage BP wreaks upon the antioxidant barrier is counteracted by its antibacterial properties (i.e. it triggers one step in the acne development process — oxidative stress — but resolves the following step — bacterial infection) so people don’t notice many issues while they’re using it religiously, apart from the dryness and irritation of course. This might however also explain why many people, including myself, notice that occasionally breakouts can flare up despite having changed nothing in their BP regimen — in these cases perhaps the oxidative damage wrought by BP temporarily surpasses its capacity to kill bacteria.

    This in effect makes benzoyl peroxide a double-edged sword (I realise that is simply reiterating what you mention in this post), and if it’s true that it depletes vitamin E to the extent that it does (at an alarming rate) then anyone that prescribes its regular use should prescribe following it up with topical antioxidants such as vitamin E (with their applications spaced out over time as it is my understanding that they might react and nullify each other’s benefits if applied one after another). Have you spread the word about this, such as on the acne.org forums where it’d be extremely beneficial to many people there? I for one wish I had known this years ago — I was on Dan’s BP regimen for 6 years, started weaning myself off at the beginning of the year, and am suffering those standard reactionary breakouts but this time have no intention of returning to the regimen ever again. And as mentioned, these breakouts are considerably worse than the ones I used to suffer from before I started the regimen many years ago.

    Has much success been reported from people using topical antioxidants in conjunction with BP or exclusively? I know it has worked for you but I’m curious if it’s caught on.

    I for one am willing to give it a shot. I’ve ordered a couple of the antioxidant-rich moisturisers you recommended elsewhere (from Madre Labs and Palmer’s), and in the meantime am moisturising with a blend of jojoba oil, sunflower oil, and olive oil (the latter two simply because they contain appreciable amounts of Vitamin E). I don’t know how effective the oil mixture will be, but if it helps in any way to replenish the skin with what BP has depleted then at least it’s a step in the right direction. I still use BP but have reduced its application significantly — now I just apply it to the areas of my face that often flare up, i.e. around the mouth and chin rather than to the entire face, and I only apply a pea-sized amount once a day. That said, I’d ideally like to reach a point where I’m no longer reliant on it, seeing as there are so many alternatives that have similar efficacy but with far less severe side-effects (and don’t cause oxidative damage), such as tea tree oil, green tea, and according to some preliminary studies even thyme (wouldn’t hurt to try!).

    I’d also like to add that I very much appreciate your site in how it serves as a counterweight to all the mainstream sites that promote excessive use of BP as the singular solution, yet also doesn’t stray into the realm of those all-natural, holistic, alternative medicine sites that consider BP the great Satan. The conclusion of BP having profound benefits as well as detriments seems to chime more with my own experiences with it. I appreciate the general principle of “less is more” that I’ve gathered from Tracy’s The Love Vitamin blog, which inspired me to wean myself off of BP, and certainly have this hope that I can be mostly clear without any topicals, but if I’m reliant on topicals that don’t have the awful side-effects of BP then that’s the next best thing. So here’s hoping to that!

    Cheers!

    P.S. Out of curiosity what is your stance on cleansers? I currently oscillate between just using water only, or my oil mixture mentioned earlier (I don’t use the “Oil Cleansing Method” popularised across the internet where they mention steaming your face with a hot washcloth and all that — I literally just use the oils like I would a regular cleanser and rinse it away).

    • Thanks for your comment, Ian.

      Yes, you are right that BP has both positive and negative effects. On the positive side it kills acne-causing bacteria, helps to peel the skin (and thus keep the pores open) and it kills the cells that trigger an immune response in the skin (a part of the problem in acne). On the negative side it causes oxidative damage in the skin and depletes antioxidants.

      Depleting antioxidants isn’t as big of a problem as it initially sounds. The skin antioxidants are constantly replenished from the bloodstream. So as long as you are well nourished that shouldn’t be a big issue.

      I haven’t talked about this at acne.org. Some years back I spent some time there but not anymore – not really interested in arguing with people over these things.

      There’s no research on combination of BP and antioxidants on acne. There is research to show topical antioxidants work. I would expect combining the two to work better as they work through different mechanisms. Taking vitamin E supplements could also work. There’s research to show that supplemented vitamin E eventually makes its way to sebum and the skin, though it can take 4 to 6 weeks before that happens. The upside of supplemented vitamin E is that it gets into all the layers of the skin. Topically applied vitamin E stays at the top most layers of the skin.

      I don’t think cleansers matter that much. I’m not sure if I really buy the stories where people say their skin got significantly less oily after they stopped washing it. It’s possible, but I remain skeptical.

      • Thanks for the informative response!

        I didn’t realise the skin replenishes its antioxidants so quickly, and regarding diet, I have a very healthy one that includes lots of spinach, broccoli, nuts, and avocados, all of which are rich in vitamin E, so that shouldn’t be an issue. Still, though, I’m left wondering that consistent overuse of benzoyl peroxide must wreak some damage that lasts in the short or medium term given the sheer plethora of cases of people suffering withdrawal breakouts that are far more severe than their acne was before beginning BP use. Perhaps in some situations it could be that their acne just worsened anyway, but I’m hard-pressed to believe that accounts for all of these cases.

        In my case, I started suffering from mild-moderate acne in my early 20’s, tried Accutane a couple times with no lasting results, and eventually stumbled upon acne.org and gave Dan’s BP regimen a shot. It cleared me up fantastically well at first, for a few months, but over time I noticed that its efficacy dropped and I was never able to remain 100% clear ever since (although I’d say maybe 90% clear not including the occasional flare-up), despite sticking to the regimen religiously. Over those years I also improved my diet and started doing exercise regularly — when I first started getting acne I admittedly had a terrible diet and lifestyle, but that has changed dramatically (I suppose one of the positive things about having suffered from acne is that it motivated me to make lifestyle choices that benefit my overall health).

        Because BP left my skin always feeling hypersensitive, dry, red, and itchy, no matter how much moisturiser I applied, I tried cutting myself off of it several times, sometimes cold turkey and other times gradually weaning myself off. Remembering how my acne was before the BP regimen, it was easy for me to decide that I actually preferred simply dealing with that level of acne than dealing with the irritation caused by BP. However, each time I quit, almost like clockwork, after 2-3 weeks I would start to get a cluster of pimples above my upper lip, and several below the corners of my mouth and on my chin. The ones above the lip would be so numerous that it’d actually be painful to open my mouth. Things like this NEVER happened before I began my BP regimen, and this is despite all the positive changes I made to my diet and lifestyle since then. The fact that it reached the point where such withdrawal breakouts were even predictable has convinced me that BP is damaging my skin’s natural protective process in some way.

        I have no reason to doubt that this damage will repair itself over time, I simply don’t know how long it will take. I’m currently going through one of these standard withdrawal breakouts as I’ve experienced several times in the past, due to having reduced by BP application to a pea-sized amount once a day only to problem areas — however I can at least say that this time it isn’t quite as severe and isn’t going to be enough to scare me back into following Dan’s BP regimen. Of course, what would also help me through this is the consolation of treating my acne topically in other, safer ways, which is why I’m very interested in antioxidant creams and supplements, and other things like tea tree oil.

        So here’s my basic regimen starting this weekend (once I return to the UK after a long stay in Budapest):
        In the morning cleanse with either just water or an AHA/BHA wash with a few drops of tea tree oil, following up with antioxidant-rich cream to moisturise.
        At night cleanse with either just water or my oil mixture (mostly vitamin E-rich oils mixed with a bit of tea tree oil), apply small amount of BP to acne-prone areas, and wait 30 minutes before following up with the antioxidant cream.
        And a daily supplement of Vitamin E, niacinamide, and zinc.

        Do you reckon that’s a good routine to follow?

        Thanks again, my fine Finnish friend!

        • I’m curious to hear what your thoughts are on what might be behind these common “worse than usual” BP-withdrawal breakouts that seem to affect so many people, as well!

          • I wouldn’t be surprised if most of them turned out to be true. The problem is that most studies don’t even touch on the long term effects of acne treatment products. Most studies run from 8 to 12 weeks and count adverse effects during that periods. Very few, if any, do any sort of long term followup. Even during the study period there are people who drop out because side effects got too severe. It’s not impossible, though far from proven, that over time side effects would get more severe. That would suggest deterioration of the skin barrier and the skin’s natural defenses and would leave the skin worse off when the treatment is stopped.

        • Hi Ian,

          The fact that BP depletes 95+ of vitamin E from the skin probably sounds more dramatic than it actually is. The skin has to constantly replenish antioxidant reserves. Think about it. The skin is almost constantly exposed to UV rays, smog and other harmful elements that require antioxidant protection. Without constant replenishment the skin would quickly fall apart from all the beating it takes.

          I’m not quite sure why people get worse breakouts after quitting BP. Perhaps because BP isn’t exactly a precision weapon. It destroys both harmful bacteria and healthy skin cells. I wouldn’t be surprised if constantly using it would undermine the skin’s protective processes. I still think it can be useful but it should be combined with topical antioxidants to replenish the lost antioxidant protection.

          Your skin care regimen looks ok. Just be careful with undiluted tea tree oil. All essential oils are quite toxic and irritating to the skin, so they have to be heavily diluted before putting on the skin.

          • Thanks again for the response!

            All those claims out there that people’s skin develops an “addiction” to BP may be far-fetched, but it’s indeed clear that it at least causes some lasting damage. I just wish there were some studies that looked into that and could elucidate us into why that happens. Because after 6 years of heaping that stuff on my face in copious amounts as per acne.org’s regimen, I’m just a tad concerned!

            It was my New Year’s resolution this year to wean myself off of BP, so that’s when I started. In hindsight I wish I had thought to treat it in other ways (topical nicotinamide, antioxidant creams, tea tree oil) as I reduced my BP application but I suppose I was under this foolish optimism that I had outgrown acne and that any I was suffering from was actually being caused by the insane amount of BP I was constantly slathering on my face (maybe that’s partially true), and that any withdrawal breakout would just be a temporary hurdle I needed to soldier through.

            I have no regrets that it’s ultimately the right decision though. For the first time in years, despite suffering these regular post-BP breakouts my skin finally “feels” normal again, i.e. not constantly sensitive and irritated. Moreover having done this I’ve discovered that a lot of my face doesn’t need BP — my forehead, cheeks, and jawline are more often completely clear than not, so it seems silly to heap BP on them everyday or at all.

            I don’t consider myself lucky enough to ever be able to count myself among those people who just quit using any topicals whatsoever and miraculously heal on their own (like all the ones lauding the caveman or water-only regimens on sites like the Love Vitamin), but if I can try this combination therapy approach of BP, antioxidants, and tea tree oil, then at least I’m not developing a reliance on any one thing in particular. Moreover, what especially appeals to me about the antioxidants is that they come in the form of a moisturiser, which is a step I don’t think I would have ever been able to part with anyway (I grew up in humid tropical Belize and Europe’s climate by comparison is very dry for me, so I need it).

            Hopefully this way I can over time wean myself off of BP completely but continue using antioxidants, and not suffer any withdrawal breakouts, like what you managed to do.

            And thanks for the advice about diluting the tea tree oil. I figured if I just used a few drops along with a cleanser then using it pure wouldn’t matter as it’d just be washed off, but then again that probably means it’d have no benefit since it’s not left on my skin. So it’s probably better that I apply it in diluted form to my face afterwards and leave it on. I’m guessing a 5% or 10% dilution in non-irritating oils (e.g. jojoba) or water would do?

            Thanks again!

          • Also, what I think lends further credence to the idea that benzoyl peroxide causes lasting damage to the skin’s natural healing process is the fact that many people report that post-inflammatory hyper-pigmentation lasts significantly longer for skin that is regularly treated with BP (I’ve noticed this as well).

          • I wouldn’t use tea tree oil in higher than 5% concentration. The problem with DIY remedies is that it might be hard to get the TTO to completely disperse into the carrier oil. So some areas could have significantly higher concentration than other areas. And while the skin might be able to tolerate more than 5%, I would keep that as maximum to account for possible uneven distribution in the carrier oil.

            Glad to hear your skin feels more normal than while using BP. Means you are on the right track.

  4. Hello, I mix benzyl peroxide with vitamin e as moisturiser before makeup in the morning. I also use neo medrol when going to bed. Is this routine okay? I am yet to see changes though but I hope it works. I’m mix because I read online that this product’s are harsh and saps the natural moisture on the face. Thanks

    • There’s a test tube study that shows mixing vitamin E increases the oxidative damage BP does, but I don’t know how relevant this is to your situation. Test tube studies aren’t always applicable to real world applications. But as a precautionary rule, I advise people to wait for 30 minutes after applying BP before applying antioxidants.

  5. I realise this is an old post but i have been using 2.5% for a year with no problem bar some redness and drying in the first 6 days. I have now found 3.0% at half the price. Is that 0.5% extra concentration of BPO likely to make side effects significantly more likely? half of one percent doesn’t sound much but i know enough about chemistry to know small increments can mean a lot.

  6. Hi! I’m currently using AcneFree’s Acne Clearing System (Cleanser with 2.5% BP + toner + lotion with 3.7% BP) on my chest and back. I was wondering if it would be safe to use Aztec clay mask (bentonite clay) on my chest and back for like twice a week even if I am using AcneFree. If it is safe, would you recommend me applying the mask on top of the BP lotion, on top of my moisturizer (applied 30 mins after BP, as you suggested), or shall I skip AcneFree if I wish to apply the mask?

    I am also thinking of buying Thayer’s rose petal witch hazel. Would it be safe to use it on my face after I wash it with a cleanser with 2% salicylic acid?

    Thank you so much! I appreciate your time and effort in answering all the questions posted here.

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